1. Field of the Invention
The present invention relates to an ink jet printer that performs printing on a sheet supported by a platen.
2. Description of the Related Art
Many ink jet printers include a platen for supporting and positioning a conveyed sheet at a printing position. When so-called borderless printing is performed and when the printing is performed on an end portion of the sheet, ink may be applied outside the sheet and adhered onto a surface of the platen.
If the next printing is performed on the sheet having a different size before the ink gets dry, the ink is adhered onto a rear surface of the sheet and stains it. To address this problem, a structure is known in which a collection opening for collecting the ink discharged outside the sheet is formed in a sheet supporting surface of the platen.
Since a distance between an ink discharge hole of a print head and a collection opening of the platen is long, a part of the ink discharged outside the sheet when the borderless printing is performed may become floating ink mist (including ink satellite). The floating ink mist can cause stains on the inside of the printer, for example, on the platen and the rear side of a media nearby.
Japanese Patent Application Laid-Open No. 2007-331255 discusses an apparatus in which the generated floating ink mist is collected by suction with a suction fan inside the collection opening, thereby preventing the floating ink mist from scattering. Further, the apparatus uses the same fan to attract the sheet onto the platen.
In the apparatus discussed in Japanese Patent Application Laid-Open No. 2007-331255 described above, a common suction fan uniformly attracts the sheet onto the platen and suctions the ink mist from the collection opening. However, a method is not discussed for ununiformly and individually adjusting a negative pressure to each of the purposes described above.
Accordingly, when the borderless printing is performed and even when bordered printing without necessity of suction from the collection opening is performed, the suction is always performed with a highest ability, thus continuing to generate a big noise of the fan. However, if the mechanisms such as the suction fan are separately provided to attract the sheet and collect the ink mist from the collection opening, the noise will be further worsened, and a size and a cost of the apparatus will be increased.